DENOVO CONSTRUCTORS, INC. WELCOME CHEMICAL AND BIOLOGICAL TREATMENTS
Jan 29, 2016
DENOVO
CONSTRUCTORS, INC.
WELCOME
CHEMICAL AND BIOLOGICAL TREATMENTS
2
CHEMICAL AND BIOLOGICAL TREATMENTS
• Chemical oxidation
• Chemical reduction
• Biological treatment
• Many technologies can be applied “in situ” or “ex situ”.
• Certain technologies can treat soil, groundwater, or both.
3
CHEMICAL OXIDATION
• In situ chemical oxidation (ISCO) – involves injecting oxidants into the subsurface to react with contaminants.
• Oxidation-reduction reactions produce harmless substances (e.g., CO2, water, inorganic chloride).
• Various oxidants are available – will depend on the type of contaminant, concentrations, and subsurface geology.
• Oxidants used, will have different oxidation potentials (relative strength).
4
CHEMICAL OXIDATION – COMMON OXIDANTS
Oxidant Contaminants Treated
Peroxide, Fenton’s Reagent
TCA, PCE, TCE, DCE, VC, BTEX, chlorobenzene, phenols, 1,4-dioxane, MTBE, tert-butyl alcohol, explosives
Ozone (injected as gas - sparging)
PCE, TCE, DCE, VC, BTEX, chlorobenzene, phenols, MTBE, TBA, explosives
Ozone + peroxide TCA, PCE, TCE, DCE, VC, BTEX, chlorobenzene, phenols, 1,4-dioxane, MTBE, tert-butyl alcohol, explosives
Permanganate (potassium or sodium)
PCE, TCE, DCE, VC, BTEX, PAHs, phenols, explosives
Activated Persulfate*
PCE, TCE, DCE, VC, BTEX, chlorobenzene, phenols, 1,4-dioxane, MTBE, tert-butyl alcohol, pesticides *Activation by iron, hydrogen peroxide, heat, or high pH (lime or
NaOH)
5
CHEMICAL OXIDATION – APPLICATION METHODS
• Direct push injection• Fixed well injection• In situ soil blending application• Ex situ soil blending application
6
CHEMICAL REDUCTION
• In Situ Chemical Reduction (ISCR)
• Zero-valent Iron (ZVI)
• ZVI + added carbon substrate – induces anaerobic reductive dechlorination by microbes.
• Targent contaminants are mostly chlorinated solvents (PCE, TCE, DCE, VC, TCA, carbon tetrachloride).
• Also can treat some pesticides and explosives.
• Often combined with anaerobic biological treatment.
7
CHEMICAL REDUCTION – APPLICATION METHODS
Injection:• Direct injection• Hydraulic/pneumatic
fracturing
Placement:• Placement into trenches or
excavations• Deep soil mixing
8
BIOLOGICAL
• Aerobic and Anaerobic Remediation Methods
• Uses natural microbes in the subsurface to degrade contaminants.
• Stimulates microbes by adding oxygen, and/or nutrients.
• Biological can be combined with chemical methods (e.g., ISCO + ORC; carbon source + ZVI)
9
AEROBIC BIOREMEDIATION - ORC
• Addition of oxygen and nutrients enhances aerobic bioremediation.
• Converts biodegradable contaminants into carbon dioxide and water.
• ORC can be applied as slurry or as a dry, solid powder
• Application methods – soil mixing/blending, direct injection, recirculating wells, direct placement into excavations or barrier walls.
• In situ or ex situ applications.
10
ANAEROBIC BIOREMEDIATION
• Addition of carbon source (e.g., lecithin, lactic acid, molasses) and nutrients (nitrogen and phosphorus)
• Enhances anaerobic bioremediation – enhanced reductive dechlorination.
• Mainly in situ applications – comes as slurry and emulsions.• Direct injections• Soil mixing• Placement into excavations
11
SPECIALTY SUPPLIERS AND PRODUCTS
• Provides chemicals and specialized products.
• Provides dosing and technical support during design.
• Some companies can provide onsite field support during application.Example Companies
PeroxyChem Regenesis
Tersus Environmental Orin
ISOTEC MECx
12
PROJECT EXAMPLE –CHEMICAL REDUCTION SOIL MIXING @ AN ARMY AMMUNITION PLAN
• In situ soil mixing of 7,500 cubic yards of clay soil contaminated with chemicals.
• Grout slurry mixture consisting of Zero valent Iron and bentonite – produced in onsite mixing plant.
• Overlapping soil columns mixed with deep-soil auger using a hollow Kelly bar
• Slurry pumped through Kelly bar to the auger/mixer equipped with injection ports.
(NTS)
MANITOWAC 4000 W SERIES
IN-SITU SOIL
12" SQUARE, HOLLOWKELLEY BAR
10-FOOT DIAMETERAUGER / MIXER
SYSTEM
14-FOOT DIAMETER OFF GAS CONTAINMENT SHROUD
CRANE (150 TONS)
HAIN TURN TABLE WITH 300,00 FOOT-POUNDS OF TORQUE
CONTROL VALVES
L-12 MOYNO PUMP
SLURRY FLOW METER
CONTROL VALVE
WATER METER4" HDPE PIPE
WATER FROM FIRE HYDRANT
5 CY HIGH-SHEAR LIGHTNING MIXER
PRESSURE METER
TO AIR TREATMENT
IN-SITU SOIL MIXING & TREATMENT SYSTEM
CONTROL VALVE
13
THANK YOU